This invention has a single annular valve at the upper end portion of a down tube in a beer keg with provision for the flow of beer from the keg across the inner circumference of the annular valve element, and the flow of gas into the keg across the outer circumference of the annular valve element. A probe with an annular end face contacts with the top surface of the valve element to provide a passage for the beer that flows from the down tube and across the inside circumference of the valve element; and the probe has a clearance around its outside surface providing a passage for gas to flow into the keg around the outside circumference of the annular valve element.
The annular valve element is intended primarily for use with a down tube that is in fixed position in the keg with the upper end of the down tube closed and with ports around the circumference of the down tube just below the upper end of the tube. The valve element slides on the down tube from a position where it covers the ports to a lower position in which the upper surface of the valve element is below the upper ends of the ports so that beer flows through the ports and into the passage provided by the tubular probe in contact with the top surface of the valve element.
The probe is movable up and down in a probe fitting and is urged upward by a spring. A handle of the probe fitting operates cam mechanism that overcomes the pressure of the spring and moves the probe downward to open the valve in the keg fitting. The probe fitting is connected with the keg fitting by a conventional bayonet type connection; and it is a feature of this invention that the handle on the probe fitting turns the probe fitting in the direction required to lock the bayonet connection and secure the probe fitting during the first part of the movement of the handle; and further movement of the handle in the same direction moves the probe downward to open the valve in the keg.
Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.